1. Field of the Invention
The present invention relates to a grinding machine, and more particularly to a grinding machine having a dust-collecting tube with an inner tube, and the inner tube is interconnected with an exhaust vent and the dust-collecting tube to produce a siphon effect for collecting dust.
2. Description of the Related Art
Referring to FIG. 6 for a traditional grinding machine, the grinding machine includes a driving portion 9 and a transmitting portion 8, and an end of the driving portion 9 has an air inlet 91 and an exhaust vent 92, and an end of the transmitting portion 8 has a grinding wheel 81, such that when air is introduced into the air inlet 91, the driving portion 9 is driven to rotate the grinding wheel 81, and air is discharged from the exhaust vent 92.
However, the aforementioned grinding machine usually produces a large quantity of dusts during the grinding process, and users may inhale lots of dusts into their lungs, and the dust contamination always causes tremendous inconvenience to the work.
Referring to FIG. 7 for another common grinding machine, the difference between this grinding machine and the foregoing grinding machine resides on that the bottom of this grinding machine includes a dust-collecting tube 7; wherein an end of the dust-collecting tube 7 has a dust-discharging opening 71, and another end of the dust-collecting tube 7 has a dust-collecting opening 72, and the dust-collecting opening 72 is situated at a working area of the grinding wheel 81. During a grinding operation, a power dust collector S is used to suck the dusts produced by the grinding wheel, and thus users need to purchase a power dust collector (such as a vacuum cleaner).
Sometimes, there is a need to remove or replace a grinding wheel 81 disposed on a lateral side of the grinding machine, but there is no protection by a fender, and users may get injured easily if the users do not hold the grinding machine firmly and steadily.